Description

2009/10/07, Dr. Ming-Hao Liu, Department of Physics, National Taiwan University, Taipei, Taiwan

Place: Sala de Seminarios del Departamento de Física Teórica e Historia de la Ciencia
Time: 12h.
Title: Electrically Reversible Spin Polarization in Honeycomb Lattices

Abstract
The spin-split states subject to spin-orbit coupling in two-dimensional systems has long been accepted as pointing in-plane and perpendicular to the corresponding wave vectors. This is in general true for free electron model, but exceptions do exist. We unveil the unusual upstanding behavior of those spins around high-symmetry points in honeycomb lattices. Our calculation  explains the recent experiment of the Tl/Si(111)-1x1 surface alloy [PRL 102,
096805 (2009)], where abrupt upstanding spin states near these points have been observed, and predicts an electrically reversible out-of-plane surface spin polarization. These results extend the ability of spin manipulation by electric field,
which is one of the goals of modern spintronics.